dql: annotate data-races around dql->last_obj_cnt

dql->last_obj_cnt is read/written from different contexts,
without any lock synchronization.

Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing.

Signed-off-by: Eric Dumazet <[e-mail]>
Reviewed-by: Joe Damato <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

include/linux/dynamic_queue_limits.h

···
 	if (WARN_ON_ONCE(count > DQL_MAX_OBJECT))
 		return;
 
-	dql->last_obj_cnt = count;
+	WRITE_ONCE(dql->last_obj_cnt, count);
 
 	/* We want to force a write first, so that cpu do not attempt
 	 * to get cache line containing last_obj_cnt, num_queued, adj_limit

lib/dynamic_queue_limits.c

···
 
 	dql->adj_limit = limit + completed;
 	dql->prev_ovlimit = ovlimit;
-	dql->prev_last_obj_cnt = dql->last_obj_cnt;
+	dql->prev_last_obj_cnt = READ_ONCE(dql->last_obj_cnt);
 	dql->num_completed = completed;
 	dql->prev_num_queued = num_queued;